Risk-Based Design of Large-Scale Flood Defence Systems

On the basis of quantitative reliability analysis of flood defence systems, two design methods are developed. The first is reliability-based design, where the optimal geometry of a flood defence system is obtained by minimising the cost of construction under a constraint on the probability of flooding of the protected area. Reliability-based design is an integral part of the second design method, risk-based design. In risk-based design, the appropriate flooding probability of a protected area is obtained by comparing the cost of protection with the risk reduction that is obtained. A case study illustrates the application of both methods.